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Great Loop Lock Reference

Thomas J. O'Brien Lock

Reviewed planning reference for lock approach, communications, and float-plan preparation.

Chicago / Illinois Waterway

Thomas J. O'Brien Lock

Chicago, IL

Latitude / Longitude41.651617
-87.567083
Phone773-646-2183
VHF Channel16/14
Operating AuthorityNot listed
Last Reviewed2026-07-09

Lock Location

Zoomed-in location for this Great Loop lock reference.

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About This Lock

Segment: Chicago / Illinois Waterway. Route status: core inland-river route from Great Lakes to Mississippi. Waterway Guide lists phone; USACE water-safety guidance says VHF 14 for Illinois Waterway locks and Ch.16 for calling/distress. Source: https://www.mvr.usace.army.mil/Missions/Navigation/Lock-and-Dam-Phone-Numbers/

Continue planning: Check Marine Weather, estimate your trip with the Boat Fuel Calculator, or review the Solo Boating Safety Guide.

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